Magnum\LA Hybrid, Different timing cover?
You need a 1970 and later timing cover and water pump. The pullys are easy to find at junkyards just look for a pickup or van with no air and get all the pullys and brackets. Make sure the cam snout is long enough to mount the fuel pump eccentric, magnums had a shorter cam snout. If you don't want the mechanical pump you can use all the same parts with a fuel pump block off plate.